Conventionally known twin-belt casting machines produce a continuously cast slab product (hereinafter called slab), which is made of aluminum or an aluminum alloy. FIG. 17 is a diagram showing a conventional twin-belt casting machine, where (a) is a side view and (b) is an enlarged view showing a downstream side of a cavity.
As shown in FIG. 17, a conventional twin-belt casting machine 1 pours such a molten metal as a molten aluminum-alloy through between a pair of rotating belt units 3, 3 which are disposed opposite each other in the vertical direction, and casts a slab S continuously (see, for example, documents 1 and 2).
More specifically, the twin-belt casting machine 1 includes the pair of rotating belt units 3, 3 each having an endless belt and facing opposed in the vertical direction; a cavity 4 formed between the pair of rotating belt units 3, 3; and a cooling means (not shown in the accompanying drawings) provided in each rotating belt unit 3. A bottom endless belt 2a of the bottom rotating belt unit 3 comprises thin metal plates, and is wound around a drive roller 5a and a support roller 6a which are spaced apart from each other. A top endless belt 2b of the top rotating belt unit 3 also comprises thin metal plates, and wound around a drive roller 5b and a support roller 6b which are spaced apart from each other. The slab S is continuously pushed out to the downstream side in the casting direction when the drive roller 5a is rotated in the clockwise direction and the drive roller 5b is rotated in a counter-clockwise direction.
The cooling means, not shown in the accompanying drawings, has a nozzle or the like for spraying coolant water, and supplies the coolant water or the like to the back surface of the endless belt 2, thereby cooling the slab S formed in the cavity 4.
A molten metal is supplied from an injector 7 or the like provided at an upstream side, and it moves at a substantially same speed as that of the endless belts 2 which move in the cavity 4, is cooled and solidified while releasing heat to the endless belt 2, held between pinch rollers 8 or the like from the downstream side, and pulled out as the slab S. Note that a body which is not completely solidified among slabs S is hereinafter called an ingot S in some cases.
Document 1: JP2004-505774A
Document 2: International Publication No. 2007/104156 brochure